Spark-plug.



E. O. SATHER SPARK PLUG.

APPLICATION FILED JULY 6 191 I.

1 ,299,04Q. Patented Apr. 1, 1919.

j ah'uwiloz E 0. Sail ies EDMUND'O. SATHER, or BERKELEY, CALIFORNIA.

SPARK-PLUG.

rename.

Specification of Letters Patent.

Patented Apr. 1, 1919.

Application filed July ta, 1917. Serial No. 178,959.

Be it known that I. EDMUND O. SATI-IER, a citizen of the United States.residing at Berkeley. State of California, have invented certain new anduseful Improvements in Spark: Plugs, of-which the following is aspecification. V p a This invention relates to an improved spark plugand has as its primary object to provide a device of this characteradapted to produce a double spark.

Theinvention has as a further object to provide a spark plug having amain or energized electrode and a ground electrode with a neutralelectrode arranged therebet-ween so that, the current from the mainelectrode will first jump to the neutral electrode for creatiug onespark and will then jump to the ground electrode for simultaneouslycreatinganother and intensified spark.-'

The invention has as a still turtherobject to provide a spark plughaving an improved mounting for the neutral electrode and wherein thesaid electrode will be practically twice the diameter of either the mainelectrode or the ground -elect-rode tor accordingly increasing thevolume of the spark and prolonging the durability of the neutralelectrode.

And the inventionhas as a still further object to provide a spark plugwhich will prove thoroughly practical in use and whercin the porcelainof the plug will be so mounted as to minimize the tendency ttiwardbreaking or cracking of the said porcelain.

' Other and incidental objects will appear as the description proceedsand in the drawings wherein T have illustrated the preferred embodiment.of the invention and wherein similar referencecharacters designatecorresponding parts throughout the several views:

Figure 1 is a side elevation of my improved spark plug.

Fig. 2 is a vertical sectional view more articularly showing theconstruction of the plug and the arrangement of the electrodes thereof,and

Fig. 3 is a'perspective view of the upper seating gasket for theporcelain of the plug,

this view being partly broken away to show the construction of the saidgasket.

In carrying out the invention my improved spark plug is formed with ametalshell 10 provided adjacent its upper extremin the county of Alamedaand- 'cclain l5. la n is intended ing material.

be used-without a packing gasket, the shell is formed with a beveledshoulder 12 but since it is sometimes necessary to use a packing gasket.the shell may. as indicated in dotted-lines in Fig. 1. be formed with aflat stop shoulder 13 for receiving such a gasket between the plug andthe cylinder of an engine. "At the upper extremity of the reducedportion'ot the shell. the said shell is formed with an internal beveledshoulder 14.

llemovably titted within the shell is a por- As herein used the term'porceto include body similar to the porcelain 15 of any suitableinsulat- Adjacent its lower extremity the porcelain is formed with anannular shoulder 16 having a lower beveled face 17 and an upper beveledface 18. Fitted be tween the face 17 of the shoulder and the shoulder'14 of the shell 10 is an annular cushioning gasket 19. Thisgasketin-cludesas particularly shown in Fig. 52. a hollow casing ofcopper or other approved material and arranged within the said casing isa preferably asbestos filling 20 providing the cushioning element of thesaid gasket. Removably fitted over the upper extremity of the porcelainto overlie the beveled face 18 of the shoulder 16 is a substantiallycup-shaped gasket 21. shown in detail in Fig. 3 of the drawings.lnterposed between the gasket and the said face is a cushioning ring 22'which is also preferably of asbestos. Screw threaded into the upperextremity of the shell 10 and loosely surrounding the porcelain isaslceve or nut 23 engaging a 'ound the upper extremity of the gasket 21and adjustable for tightly connecting the porce lain with the shell 10.It will accordingly be observed that the porcelain will thus be heldbetween the gaskets 14 and 21 which will. in connecting with thecushioning ring 22. act to cushion the porcclainaipon the shell and thustend toprcvent the breaking or (racking thereof by the expansion orcontraction of theshell or porcelain.

Fitted through the porcelain 15 is a main or energized electrode 24, theupper extremity of which is bent; to provide a laterally directedcontact terminal 25' overlying the upper end of the porcelain. F ittedthrough the porcelain to extend in parallel-espaced relation to the mainelectrode 24 is a neutral electrode 26 formed with a crimped upperterminal 27. The terminal 27 of this electrode is received within arecess 28 in the porcelain 15 and arranged within the said recess isa'plastic filler 29 engaging with the crimped terminal 27 of theelectrodefor securely connecting the said electrode with the orcelain.Mounted upon the lower extremity of the shell 10 is a ground electrode30 heat to extend toward the electrode 26 as is also the adjacentextremity of the main electrode 24 and in this vconnectionitwill beobserved that the neutral electrode is'substantially one and a halftimes the diameter of either the main electrode or the ground electrode.Fitting over the upper end of the porcelain 15 is a metal cap 31recessed-to receive the contact terminal 25 of the main electrode 24 andseating against the upper terminal I of the porcelain. #The free edge ofthis cap standing from the cap is a binding post 34: and screw threadedupon this post is a bindling nut 35 for connecting a circuit wire withis pressed into an annular channel 32 in the upper extremity of theporcelain for securely connecting the cap thereto. Arranged within thesaid recess of the cap to surround the Contact terminal 25 is a. plasticfiller 33 acting to firmly seat the cap and hold the said terminal inengagement therewith. Up-

fi ed snark. A douole sparknvill thus be produced. Furthermore, byforming the neutral electrode 26 of larger diameter than the otherelectrodes. a spark of correspondingly increased volume will be had ateach ofthe spark aps .veen the main and ground electro es and theneutral electrode while at the same time the dura'bilit of the neutralelectrode will also be enhanced. Also, it will be further noted thatowing to theprovision of the contactteri'ninal 25 at the upper end .ofthe main electrode 24, a correspond ingly increased bearing area betweenthe said terminal and the ca 31 will be obtained so that eilicientelectrical connection between. the binding post 34 and themain electrodewill at all times be had.

It -will therefore be seen that I provide a particularly efiicientconstruction for the purposes set forth and a spark plug which willprove thoroughly practicalin use while at the same time the plug ischaracterized by simplicity of structure and may thus be manufactured atmoderate cost.

Having thus described the invention, what 6 is claimed as new is:

A device of the character described including a shell, a groundelectrodeconnected thereto, a.porcelain mounted upon the shell and provided witha recess, a main clectrode mounted upon the porcelain, a new tralelectrode carried by the porcelain to cooperate with the main and groundelectrodee l and provided with a crimped upper terminal received withinsaid recess, a filler with- 7 5 in said recess and engaging the saidcrimped terminal for rigidly connecting the neutral electrode with theporcelain.

In testimony whereof I aflix my signature.

EDMUND O. SATHER. [as]

